ISIS is a splined interface bottom bracket/crank design used by Truvativ, FSA, Raceface and other brands. FEATURES: Aluminum cups require TruVativ or compatible installation tool Heat-treated chromoly spindle for high stiffness and moderate weight Precision full-complement sealed cartridge bearings M15 crank bolts included Three bearings with two on drive side for extra life SPECS: Spindle Interface Type: ISIS BB Shell Width (mm): 68 , 73 Bottom Bracket Shell I.D.: 1.37 Spindle Length: 113 BB/Frame Interface: English Weight: 243